There are many wonderful summer programs for art and design students during the summer. Many of them have applications due in March, This is not an all inclusive list so feel free to post a recommendation in the comments section below.
Here are a few links to some summer programs for high school students:
MassArt Summer Program for Grades 11-12
Museum School of Fine Arts
Montserrat College of Art
Architecture Summer Programs
Wentworth Institute of Technology Architecture Summer Workshop
Boston Architectural College Summer Program for High Schoo Students
Carnegie Mellon Summer Program in Architecture
AND here are some more:
Link to list of Pre College Programs around the country in Architecture
Christina Chang teaches art and design to students in grades 9-12.